Endermen teleport to dodge arrows. Endermen teleport out of water when they touch it. Endermen teleport a lot more. (Guessing) Endermen have more health. (Took 4 hits with a Diamond Sword. I don't know if that's any different).

In addition to what UnwiseSudai said, the purpose of panes is also to look good in a different way than regular glass. The fact that they're made of glass makes their old behavior a bug. This is unfortunate, but more consistent.

There's still block air, unfortunately. The hitbox, although fixed for walking through it, still isn't confined to the fence post. ie, you can still "mine" the air and if you try and shoot an arrow through the "air" it will still hit it...

If you fall from a cliff and throw one when you almost hit the ground, will you only take the teleport damage, and no fall damage?

EDIT- Based on some unscientific testing on creative mode, despite being able to have the appearance of throwing items downwards, they do not fall as fast as you do, so you will hit the ground first. The question remains to if Mojang was smart enough to realize this would happen, and keep you from teleporting when the Ender Pearl lands (if you throw an item upwards near the top of your fall, you have a good second or two after you hit the ground before it hits that you can potentially use to respawn, and be instantly teleported to where you died). I'd test this myself, but I don't have any Ender Pearls or MCEdit.